#include<iostream>
#include<string>
//#include<typeinfo> //for typeid()
using namespace std;

void test_literal() {
   cout<<"hi"<<endl;
   cout<<"添加黑心起雲劑"<<endl;
   cout<<L"添加黑心起雲劑"<<endl; //garbage?
}
void test_concatenation() {
   string a="A";
   for(int i=0; i<20; i++) {
      cout<<a<<endl;
      a+="A";
   }
   //how to concate string and numbers???
}
void test_substr() {
   string clsdef="01234567890";
   cout<<clsdef<<endl;
   //cout<<clsdef.substr(5, 10)<<endl;
   //cout<<clsdef.substr(-1, 5)<<endl;
   cout<<clsdef.substr(1, 5)<<endl;
}
int main() {
   //test_literal();
   //test_concatenation();
   test_substr();
   return 0;
}
